The invention relates to an arrangement for the intermediate storage of a yarn at a spinning machine between a delivery device and a device which establishes a yarn connection during a piecing and which contains a suction pipe taking in the yarn as a loop, this suction pipe being provided with a profiling for keeping the two yarn strands of the loop separate.
In a known arrangement of the initially mentioned type (DE-C-27 28 620), a suction pipe is provided which is equipped with a partition extending in its longitudinal direction which is fastened at one of the side walls of the suction pipe. As a result, the space of the suction pipe is divided into two parts, by means of which a balling up is to be prevented in the taken-in yarn. This suction pipe is to be used in connection with an air spinning machine and in connection with a knotting arrangement.
A suction pipe which is used as an intermediate storage device is also known (DE-B-28 02 913) and has a narrowing in its center so that the cross-section is divided into two partial areas, in which the two strands of the yarn loop are to be kept separate from one another.
It is also known (JP-A-59-186 873) to produce diminished cross-sections in a suction pipe by means of inserts. In this construction, it is also provided that the suction pipe forms a meandering intermediate storage device.
In the case of an open-end spinning arrangement, it is also known (DE-B 22 21 316) to take up, by means of a suction pipe, a yarn length which is generated during the piecing operation as a result of the fact that the newly pieced yarn is withdrawn faster than it is taken up by the spool package which requires a longer start-up time. In this construction, the suction pipe has a bend, by means of which the suction forces apply force components to the strands of the yarn loop by which the two yarn strands are moved toward one another.
An object of the invention is to provide an arrangement of the initially mentioned type which is also suitable for very high delivery speeds, i.e., which must take up longer yarn lengths than in the case of the state of the art.
This object is achieved in that the suction pipe is bent in such a manner that, it has supports which are separated from one another for the yarn strands in the axial direction parallel to the axis of the bend.
By means of this bend and support arrangement, it is achieved that the suction forces exercise components on the two yarn strands by means of which these are deposited at separate points at supporting surfaces formed by a wall or the like, so that is is ensured that even a yarn loop having a relatively long length does not twist around itself. In contrast, the yarn strands, as a result of the components of the suction air flows caused by the bend, place themselves against the corresponding support areas. The loop thus keeps a defined shape.
In a further development of certain preferred embodiments of the invention, it is provided that the radius of the bend of the suction pipe is larger than the length of the suction pipe. As a result, it is ensured that the occuring friction forces to not become too high.
In a further development of certain preferred embodiments of the invention, it is provided that the profiling is divided into several sections in longitudinal direction of the suction pipe. This is completely sufficient for still keeping the yarn strands separately in a perfect manner.
In a further development of certain preferred embodiments of the invention, it is provided that the suction pipe is constructed as a flat pipe which has a central contracted area between two larger lateral cross-sectional areas. This type of a pipe may be produced from a circular pipe.
In another development of certain preferred embodiments of the invention, it is provided that the suction pipe is constructed as a flat tube which is bent around its longitudinal axis. The convexly curved bottom, which preferably forms an area of a reference cylinder, is used as the separating element which keeps the two yarn strands apart. A diminished cross-section is not required inside the suction pipe.
In a further development of certain preferred embodiments of the invention, it is provided that several suction pipes are provided which consecutively take up yarn loops. In this development, the yarn length to be taken up is divided into several yarn loops which are each shorter than one single yarn loop taking up the same length, so that then the yarn loop can be held even better in this manner in that no tangling of the yarn or the like can occur.
Other ojects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.